This invention relates to a resectoscope apparatus for resecting and coagulating tissues within a body cavity.
Recently, there is extensively utilized an endoscope apparatus whereby internal organs within a body cavity can be observed by inserting an elongate insertable part into the body cavity or various therapeutic treatments can be made, as required, by using treating instruments inserted through a treating instrument channel.
As the above mentioned endoscope apparatus, there is a high frequency endoscope apparatus for resecting a prostate, uterus interior, ureter interior or renal pelvis interior. As such high frequency endoscope apparatus, there is a resectoscope apparatus whereby such treatment as the resection of a prostate can be made by inserting the insertable part into the bladder through the urethra and passing a high frequency electric current through a resecting electrode as shown, for example, in the publication of a Japanese Utility Model Application No. 149616/1985.
Generally, a resectoscope apparatus comprises a hollow sheath to be inserted into a body cavity, an operating part having a slider removably fitted to the rear end side of this sheath and an observing scope (optical sighting tube) removably fitted from, the rear end side of this operating part which can project out of and retract into the rear end side of the operating part and an electrode made like a loop and branched into two branches at the tip for the resection of tissues within a body cavity. The operating part is provided with a guide tube made of a metal to insert the scope. The guide tube projects forward from a metal sheath connecting part of the operating part where it is inserted into the sheath and is provided on the outer periphery rearward from the sheath connecting part with the above mentioned slider so as to be slidable forward and rearward. An electrode inserting tube inserting and guiding the above mentioned electrode is provided in parallel with the guide tube. The electrode inserted through this electrode inserting tube is inserted further into an electrode inserting hole of the above mentioned slider and is fixed to an electric contact within the slider. When the electrode is contacted with an affected part and the slider is moved forward and rearward while flowing a high frequency electric current, with the forward and rearward movements of the electrode, the affected part will be able to be resected or coagulated.
However, in the resectoscope apparatus of such formation as is mentioned above, such liquid as an irrigating liquid is likely to enter the electrode inserting hole and, in case the liquid comes in, an electric path will be formed between the guide tube and electric contact and the electric current will leak into the guide tube.
In case the slider is moved forward, the slider will be in close contact with the sheath connecting part and therefore the current will leak between the electrode contact and sheath connecting part.
If the current thus leaks between the electric contact and guide tube or sheath connecting part, it will flow from the sheath or operating part to the patient and operator and will be likely to cause a burn or electric shock.